How money is not the only barrier to Aids patients getting hold of drugs

Look, I realise this is beginning to feel like one of those big containers where the Americans play Britney at you over and over again until you confess to crimes you haven't committed. I'm totally ready to move on from nutritionists. But Patrick Holford yesterday found his way on to the letters page to repeat his mindboggling claim that vitamin C is better than the Aids drug AZT, and you can't let that kind of thing lie.

Dealing with Holford is like playing Bad Science Bingo. He promotes fish oil supplements by Equazen, the company behind the Durham fish oil "trials". He is feted by Tonight with Trevor McDonald, the people fisked by Ofcom for inappropriately promoting the Dore "cure" for dyslexia. He runs his own prominent, methodologically inept experiments on schoolchildren. He has a non-qualification (an honorary diploma conferred upon him by the Institute for Optimum Nutrition - which he founded - when he was director). And so on.

But the science is the thing: what is Holford's evidence for this bizarre, repeated Aids claim? Firstly, he cites two small studies done on cells in a dish on a laboratory bench, using vitamin C and AZT. This is farcically weak evidence, blatantly unfit for purpose, absurdly reductionist.

But his second piece of evidence is more worrying: a letter from Raxit Jariwalla, the man responsible for the research, who says Patrick is right about this vitamin being better than an Aids drug. Patrick brandishes this, and I find this almost as bizarre as his claims about HIV: because there are some people you do not befriend.

Matthias Rath is the multimillionaire vitamin salesman who aggressively sells his message to Aids victims in South Africa that Rath vitamin pills are better than medication. He has contributed in large part to a madness that has let perhaps hundreds of thousands of people die unnecessarily. Who is Holford's saviour, Jariwalla? According to the Rath Foundation website, he is a "senior researcher" at the "Dr Rath Research Institute in California".

Nice friends, Patrick. And he complains, conspiratorially, that there are no trials of vitamin C in HIV. Might you expect vitamin C to beat the drug AZT in a trial in humans? It has serious side effects, but AZT was the first and only HIV medication on the market for eight years, it stopped HIV from being an automatic death sentence, and it is still in routine use as part of "combination therapy". It works, and it cuts HIV transmission, mother to baby, from 25% to 8%: which is good, since 3 million are dead already from Aids, 500,000 of them children, and at least 40 million people are HIV positive. Good nutrition is important, but vitamin C is unlikely to prove to be better than medication.

Aids is serious, and money is not the only barrier to getting hold of drugs. Nevirapine, a follow-up drug, in a single dose reduces maternal HIV transmission from 25% to 15%. It's given away free for that purpose by the drug company but in many places it is rejected by people who have been misled by vitamin-peddling anti-medication entrepreneurs.

This isn't about diet and health. And it's not about qualifications or money: it's about whether the behaviour of some cells in a dish mean that it's safe, responsible, proportionate and sane to make pronouncements about one of the biggest killers of the modern age that your innocent viewers will take seriously.

Holford is going on a speaking tour of South Africa next month. My blood runs cold at the thought. If McKeith is a danger to the public understanding of science, Holford, in this case, may be that danger realised: the last thing you knew he was on GMTV and Tonight with Trevor McDonald, chatting about stuff like tiredness. I don't expect one of those TV producers, who have given Holford a platform, to give the matter a second thought. He makes good entertainment.